1. Field of the Invention
The object of the present invention is a movement detector with automatic adjustment for detecting movement within a predetermined space as a function of conditions detected within the space monitored, intended in particular for the protection of automobiles, apartments, etc.
2. Background Art
The devices known at present for the protection of automotive vehicles simultaneously offer two types of protection, namely:
boundary protection, which employs contacts at doors, motor hood, trunk lid, sunroof, etc.; and
space protection which protects the inside space of the car by means of detectors generally put in place by the person installing the protection system. These detectors may be infrared, ultrasonic, infrasonic or ultra-high frequency detectors.
In general, a good security system, therefore, comprises:
a control board which manages the information supplied by the different detectors just mentioned;
a space detector; and
an acoustic alarm which is sounded in case of intrusion.
Among the space detectors employed up to the present time, the one most generally used is the ultrasonic detector, which constitutes an effective system of detection but, nevertheless, has certain drawbacks, the installing thereof being subject to a number of constraints, namely:
it is necessary to hermetically to close all the windows of the doors and all the vent holes of the vehicle in order to avoid any vibratory movement in the space protected, and therefore any inadvertent triggering; and
the transmitting and receiving parts of the system must be installed in a clearly evident manner and without obstacles between them, which makes them completely vulnerable (to tearing off, blocking, etc.).
It can in no case be installed on so-called convertible cars.